US 7994955 B2
The invention provides a system of generation of multi-channel analog output signals, from a single analog input signal, and the controlled activation of peripheral devices responsive to the multi-channel analog output signals. A single-channel to multi-channel analog-to-analog converter is provided to convert the single analog input signal to multiple output channels. Uni-directional coupling is used for coupling and mixing the multi-channel outputs and transferring the mixed outputs to a data bus. Signals on the data bus are used to drive the multiple peripheral devices.
1. Lighting apparatus comprising:
an analog input;
a plurality of analog outputs;
a control circuit configured to provide analog output signals at each of the analog outputs, the control circuit embodying mappings corresponding to each of the analog outputs, the mappings relating values of an analog input signal presented at the analog input to corresponding values of the analog output signals,
wherein, the mappings are such that increasing the value of the analog input signal from a minimum value to a maximum value causes each of the analog output signals to vary according to a corresponding waveform; and
wherein the waveforms each include a ramp portion wherein the corresponding analog output signal ramps up to a peak value and holds at the peak value for a sub-range of values of the analog input signal.
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the bus lines comprise at least first second and third bus lines,
a first one of the outputs is connected to drive the first bus line,
a second one of the outputs is connected to drive the first and second bus lines, and,
a third one of the outputs is connected to drive the first, second and third bus lines.
12. Lighting apparatus according to
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This application is a continuation of U.S. application Ser. No. 12/031,452 filed 14 Feb. 2008 entitled: SYSTEM OF MULTI-CHANNEL ANALOG SIGNAL GENERATION AND CONTROLLED ACTIVATION OF MULTIPLE PERIPHERAL DEVICES. This application claims the benefit of U.S. application Ser. No. 60/927,122 filed 2 May 2007, the content of which is hereby incorporated by reference.
The invention relates generally to the field of controlling multiple devices. In particular, the invention relates to a system of generation of multi-channel analog output signals, from a single analog input signal, and controlled activation of multiple peripheral devices responsive to the multi-channel analog output signals.
Currently, digital technologies are widely used in information and communication applications. While digital representation of information may provide improved precision, human sensory functions are believed to be fundamentally analog in nature. Frequently, information, although represented in digital form, is communicated to human users in analog form. For example, it is routine to digitize an image but present the image on a display device, with digitized signal strength converted to brightness of a light emitting element of the display device.
As is generally known, digitized signals are typically represented in discrete elements, such as bits. The relative range and resolution of a signal that can be represented in digital form are limited by the number of bits used to represent signal strength. Increasing the number of bits increases the range and resolution of the signal that can be represented in digital format. However, demand on data storage, data transmission and data generation also increases as more bits are used. Simply increasing the number of bits therefore may impose an unacceptable burden on energy consumption, data processing capability, and requirements on data transmission bandwidth and data storage.
Briefly, the invention relates to a system that generates multi-channel analog output signals from a single analog input signal. The invention also relates to controlled activation of multiple peripheral devices responsive to multi-channel analog output signals so generated. The system includes a single-channel to multi-channel analog-to-analog conversion engine, a uni-directional coupling unit that provides a uni-directional coupling of output signals of the conversion engine to a multi-channel data bus but inhibits any feedback of information from the data bus, and a drive module that interfaces the signals on the data bus to the peripheral devices to achieve controlled activation of the peripheral devices responsive to signals on the data bus.
In a first aspect of the invention, there is provided a system for controlling a group of peripheral devices responsive to variation of a single analog input signal within a range. The system includes a single-channel to multi-channel analog-to-analog signal converter for converting the single-channel analog input signal to a plurality of analog signals, the range being partitioned into a plurality of sub-ranges, a data bus having a plurality of bus lines, each of the bus lines being operatively connected to one peripheral device of the group of peripheral devices for controlling operation thereof; and a uni-directional coupling unit, the uni-directional coupling unit operatively transmitting each of the plurality of sub-range analog signals to at least one of a plurality of bus lines of the data bus and inhibiting any feedback from the bus being transmitted to the analog-to-analog signal converter. The analog-to-analog signal converter has a plurality of sub-range signal generators, each of the plurality of sub-range signal generators being responsive to the analog input signal within a sub-range of the plurality of sub-ranges to generate a sub-range analog signal. The sub-range signal generators may comprise linear amplifiers.
In a feature of this aspect of the invention, each sub-range signal generator comprises a first circuit path and a second circuit path. The first circuit path is responsive to the analog input signal within the sub-range and tends to cause an output of the signal generator to gradually increase in response to increase of the analog input signal when the analog input signal is in the sub-range. The second circuit path is responsive to the analog input signal within the sub-range and tends to cause the output of the signal generator to gradually decrease in response to increase of the analog input signal when the analog input signal is in the sub-range. The first circuit path and the second circuit path cooperate to generate the sub-range analog signal in the sub-range.
In another feature, the analog-to-analog signal converter comprises a light source and a plurality of light detectors. Each of the plurality of light detectors corresponds to one of the plurality of sub-ranges. Detection of light from the light source by the each light detector produces the sub-range analog signal. The plurality of light detectors are spaced from each other, the light source is movable relative to the plurality of light detectors, and the relative movement is responsive to the analog input signal.
In yet another feature, the analog-to-analog signal converter comprises a first magnetic coupling element and a plurality of secondary magnetic coupling elements, each of the plurality of secondary magnetic coupling elements corresponding to one of the plurality of sub-ranges, the plurality of secondary magnetic coupling elements being spaced from each other and from the first magnetic coupling element, the first magnetic coupling element being movable relative to the plurality of secondary magnetic coupling elements, the relative movement being responsive to the analog input signal, and variation of coupling between the first magnetic coupling element and the each secondary magnetic coupling element producing the sub-range analog signal.
In another feature, the unidirectional coupling unit comprises a plurality of diodes, each of the plurality of diodes coupling an output terminal of one of the plurality of sub-range signal generators to at least one of the bus lines.
In yet another feature, the uni-directional coupling unit comprises a plurality of photo-electric couplers, each of the plurality of photo-electric couplers coupling an output terminal of the each of the plurality of sub-range signal generators to at least one of the bus lines.
In other aspects the invention provides various combinations and subsets of the aspects described above.
For the purposes of description, but not of limitation, the foregoing and other aspects of the invention are explained in greater detail with reference to the accompanying drawings, in which:
The description which follows and the embodiments described therein are provided by way of illustration of an example, or examples, of particular embodiments of the principles of the present invention. These examples are provided for the purposes of explanation, and not limitation, of those principles and of the invention. In the description which follows, like parts are marked throughout the specification and the drawings with the same respective reference numerals.
In one embodiment, the input analog signal is a voltage value of an input source. Conveniently, this input analog signal can be supplied to the system through a power supply wire. An optional DC (direct current) overflow circuit 112 is provided that is coupled to both the analog-to-analog signal converter 104 and the input module 102. The overflow circuit 112 passes power supply voltage to the analog-to-analog signal converter 104 to power its operation. The overflow unit 112 also allows a margin voltage extracted from supply voltage, namely a portion of the supply voltage in excess of the system's internal regulated voltage, to be used as input, thereby allowing a single wire control and powering of the entire device or system. The internal regulated voltage is lower than the supply voltage and is used as a reference voltage for the overflow unit 112 to extract the margin voltage.
As described above, the input module 102 accepts as input a single-channel analog signal. Input is generally an analog, continuous signal. The input signal may be a continuous voltage or current signal representing (i.e., converted from) a variety of monitored signals, such as temperature, speed, relative position, ambient brightness, or applied force. The input signal also may be stepped or a composition of signals, represented in a cumulated analog form, such as an accumulated unit number from a production line. The input also may be a manually adjustable electric voltage or current. The analog signal may take the form of alternating current (AC), direct current (DC), value of a variable resistor (VR), or as a photoelectric input (PE), just to name a few examples. Conveniently, converters to convert one type of input signal, such as temperature, sound or speed, to another type of signal, such as electric current or voltage, can be provided in the input module 102.
The single-channel analog signal varies within a range, between a minimum and a maximum value. The range can be partitioned into a number of sub-ranges, the union of all sub-ranges being the range of the analog signal. Each of the sub-ranges overlaps with its neighbors, though it is understood that at either end of the range a sub-range has only one and therefore can only overlap with one neighbor.
As VIN varies within the range 200, the system 100 generates, as an intermediate step, a multiplicity of output analog signals, namely V1, V2, V3, V4, . . . , VN, corresponding to the sub-ranges. In other words, the system 100 maps an analog input (VIN) in a single channel to outputs of multiple channels (V1, V2, V3, V4, . . . , VN). The mapping is typically continuous. Each output analog signal is mapped from the variation of VIN within its corresponding sub-range R1 (202), R2 (204), R3 (206), R4 (208), . . . , RN (210), to V1, V2, . . . , VN, as VIN increases from a lower bound of a sub-range to an upper bound of the sub-range. The variation of Vi in its corresponding sub-range Vi defines a waveform 216. For example, as VIN increases, the output signal 216 corresponding to a sub-range Vi increases gradually from its initial value (for example, zero) in an up-take region 218 until it reaches a peak value. The output signal 216 may remain generally constant in a portion of the sub-range as VIN continues its increase (thereby forming a peak region 220) and then decreases gradually, generally back to (but not necessarily) its initial value (forming a decay region 222). The up-take region 218, peak region 220 and decay region 222 together form a profile of the output signal, or “wave form” of the output signal. The durations of each of up-take region 218, peak region 220 and decay region 222 are adjustable, as will be described later in more detail in examples provided below. For example, up-take region 218 may have a duration longer than the decay region, or vice versa. The increase in the up-take region 218 and the decrease in the decay region do not need to be linear, and can take any shape, or even with reflection points, as long as the general trend remains generally increasing or decreasing. Similarly, the peak region 220 may have any duration and may be absent (zero duration) and is not necessarily flat.
One example of output analog signals is illustrated in
The output analog signals are generated by the analog-to-analog signal converter 104. Conveniently, the analog-to-analog signal converter (or the input module itself) partitions the input range 200 into multiple sub-ranges.
Conveniently, the analog-to-analog signal converter 104 provides a sub-range signal generator 400 for each sub-range. The waveform within each sub-range is determined by the construction of the corresponding sub-range signal generator 400. The width and position of a sub-range can be further fine tuned by adjusting component properties of circuit components employed in the corresponding sub-range signal generator 400.
Each of the transistors T1, T2 is part of a circuit path in the sub-range signal generator 400. The first circuit path 402 comprises transistor T1 and its base current limiting resistor R1. The base current limiting resistor R1 is connected to sub-range output VA, i.e., directly to the input voltage, VIN. The second circuit path 404 comprises transistor T2 and its base current limiting resistor R2. The base current limiting resistor R2 is connected to sub-range output VB, i.e., at a level approximately 0.6V lower than VA. The first circuit path 402 drives the load resistor RL, supplying the current source for the signal at the resistor RL. The second circuit path 404 is a shunting path to ramp off the first circuit path 402 and therefore may also be regarded as a self-shunting circuit path.
The bipolar junction transistor T1 may remain in the high state for some range of values of the input, thereby forming the peak region 220. Meanwhile, as input voltage continues its increase, VB will start to increase and will eventually overcome the voltage drop across diode DA and provide a forward biasing for the second transistor T2. This represents the on-set of ramping off of the first circuit path 402. As the input continues to increase, the collector current of T2 will increase. However, any current flowing through the collector of T2 shunts the current flowing into the base of transistor T1, thus gradually returning T1 from its maximally conducting state to its linear region, until T2 becomes maximally conducting. Thus, as the current through T2 increases, the current through T1 decreases. This forms the decay region of the waveform 216 and completes the output waveform shown in
In other words, while transistor T1 in the first circuit path 402 provides pull-on of signal, i.e., current in RL, transistor T2 in the second circuit path 404 provides a self-shunt, pull off of the first circuit path 402. The on-set of pull-on determines the lower bound of the sub-range. The complete pull off effected by the ramping on of the second circuit path 404 determines the upper bound of the sub-range. The delayed ramping on of the second circuit path 404 cooperates with the pull on of the first circuit path 402 to produce a desired profile of the output waveform. Both the width and the position of the sub-range are affected by the sub-range voltage outputs at, for example, VA, VB, and by values of the base resistors, R1 and R2, and therefore can be adjusted by adjusting characteristic values of these circuit elements. For further adjustment, emitter resistors may also be added to each of the transistors to fine tune the range and overlap. It will be appreciated that adjusting the profile in one sub-range also changes the overlap with profiles of neighboring sub-ranges when the profiles of the neighboring sub-ranges remain the same.
As described above, each sub-range has a corresponding sub-range signal generator 400. Referring to
The combination of the voltage divider portion and the series of sub-range signal generators 400 forms an analog, self-shunting DC voltage/current ladder. The ladder can be of any length. In other words, range 200 of input signal can be of any value and can be partitioned into any number of sub-ranges. As the input varies from its minimum to its maximum, a wave having the waveform 216 transitions from the lowest step, namely the lowest sub-range, progressively, to the top of the ladder, namely the highest sub-range.
As will be appreciated, voltage dividers may be conveniently formed using resistors, or any other suitable means, not necessarily diodes. For example, a voltage divider consisting of only resistors can be used to replace the string of diodes in
As VIN increases and exceeds 0.1V, the first output terminal 416 is first set to “L” which subsequently toggles the output level of second op-Amp 1B and sets the second output terminal 422 to “L”. As VIN continues to increase, but still remains smaller than the 0.2V, the second op-Amp 2A the level at the second output terminal 422 remains at “L”. When VIN exceeds 0.2V, the second op-amp 2A is switched to “L”, which causes the second op-amp 1B to switch off the first channel and returns the output at the second output terminal 422 to “H”. The resistors R1A and R1B connected between the output and negative terminals of the op-amps 1A, 1B, respectively are to configure the op-amps 1A and 1B to operate also in the linear region, in addition to being able to switch between “H” and “L” levels.
In another embodiment, a sub-range signal generator 400 is constructed from logic gates.
Consider the case where the input signal increases over time from a small valve. Resistors 439A and 439B divide the voltage difference between the output of gate 437 and node 433A at node 440, which is connected to both inputs of gate 437. The output of gate 437 is initially high (since the voltage at node 433A is initially low). The output of gate 437 connects to one input 442A of gate 438. The other input 442B of gate 438 is connected to the output of a voltage divider made up of resistors 443A and 443B. Therefore, the output of gate 438 is initially high. As the input signal increases, the voltage presented at input 442B increases to a point at which the output of gate 438 begins to decrease. As the input signed continues to rise, the voltage rises at the inputs to gate 437 until eventually the output of gate 437 begins to go low. When this occurs, the output of gate 438 begins to go high again. This same pattern occurs for each of circuits 436 but is shifted relative to the input signal.
The output signals of all sub-range signal generators 400 form the outputs of the analog-to-analog signal converter 104, each sub-range corresponding to a unique channel. Referring to
The selection of diodes and connection to different bus lines depends on the designation of each individual output channel. For example, in the example illustrated in
As another example, a further “white” data bus line LW may be provided, for coupling to signal VW that is generated when the input has a value between that to generate VOUT5 and VOUT6. A signal on the bus line LW controls a white color LED. Thus, when VIN increases within its range, the color of light varies from red to green, from green to blue, from blue to white and then back to red. Other methods of providing white light also may be used to generate this color sequence. For example, “white” may be generated by mixing suitable amounts of red, green and blue colors. Empirically, it is found that a R:G:B ratio of 30:59:11 produces an acceptable “white” color as perceived by human eyes (“perceived white”).
These diodes, D1, D2, D3, D4, D4′, D5, D5′, D5″, D6 etc. form a diode array 500. This diode array 500 provides a one-way isolation between output channels of the analog-to-analog signal converter 104 and the data bus 108. The uni-directionality here is provided by diodes in the diode array. The uni-directionality allows DC information to pass through and to be transmitted to the data bus 108 but does not allow any feedback from the data bus 108 to be transmitted back to the analog-to-analog signal converter 104. As will be appreciated, coupling elements other than diodes may be used for providing the one-way coupling. Examples of uni-directional coupling units that use other coupling elements possessing uni-directionality are provided below.
The provision of the data bus 108 helps streamlining the passing of information from the analog-to-analog signal converter 104 to control peripheral devices. In the embodiment shown in
Although LED arrays are used in these examples to illustrate the output characteristics, the signals on these bus lines can be used to drive other peripheral devices, not necessarily an LED array. For example, the LED examples provided herein illustrate the lighting of LEDs driven by the resulting drive currents. These same currents may also be used to drive a multitude of motors, provided the driver circuitry supplies sufficient current. The motors may be used to manipulate (or control) motion of a robot, for example. These currents also can be used to control operation of peripheral devices requiring input of more than one phase, such as multi-phased currents or voltages. For example, the multi-channel output signals may be conveniently used as the output of a single phase to multi-phase converter for driving a multi-phase motor, using a single phase alternating current input. Alternatively, each output channel may also drive an analog/digital converter thereby interfacing the system with a digitally driven device, or devices. In general, driver circuitry may be provided to convert signals on the data bus to drive current or voltage loads.
Optionally, a gate/interface component 110 is provided between data bus 108 and peripheral devices as the driver circuitry, to enable the information, i.e., signals on the data bus 108, to be utilized by a wide range of peripheral devices. In one embodiment shown in
Conveniently, for certain applications, it is desirable to use a single wire to supply voltage to the system as the power source and to the input module as input signal. This may be, for example, an application where three colored LEDs are used to indicate the voltage of a power supply by changing emitted colors. A DC overflow circuit 112 extracts any excess voltage above a nominal (i.e., internal regulation) voltage of the system and provides this “overflow” to the input module 102 as an input signal. This is illustrated in
Output of each channel is coupled to a bus line through a diode in the uni-directional coupling unit 106. The diodes for coupling each output channel to the data bus form a diode array 500. As described above, the diode array 500 provides a uni-directional coupling of output signals from sub-range signal generators 400 to the data bus 108 and isolation of any feedback from the data bus 108. In addition, as described above, the diode array 500, with its connections to the data bus 108, also provides mixing of signals from different output channels, for example, a mixing of signals from R/B channel and R channel at the R bus line and a mixing of signals from R/B channel and B channel at the B bus line. Also provided by the diode array 500, with its connections to the data bus 108, is the splitting of signals from a selected output channel for coupling to different bus lines.
Each output phase, i.e., signal from each bus line, has its own drive circuit to drive a peripheral device, in this case, a colored LED. The LED array 706, comprising LED diodes DB, DG and DR, constitutes the peripheral devices in this example. Each drive circuit works in its linear amplification portion. For example, the output of the blue channel, or signal on the blue bus line, is coupled to the base of the bipolar junction transistor TB, which in turn amplifies the signal and drives a blue color LED LEDB. The intensity of drive current corresponds to the strength, or value of the output received from the conversion engine. As the signal on the blue bus line reaches its peak, the drive current also reaches its peak, thereby driving the intensity of blue LED to its brightest level. Similarly, LEDs of other colors, namely a green LED LEDG and a red LED LEDR, are driven by their respective drive circuits comprising bipolar junction transistors TG and TR.
To provide further control, a gate circuit comprising a first gating bipolar junction transistor TG1 controls all drive circuits for all channels in the gate/interface component 110. Thus, the transistor TG1 controlled by the control signal, can selectively decouple all peripheral devices from signals on the data bus. The control signal may be supplied through a control bus line (not shown) or any other suitable means. The ability to turn on and off of the entire LED array facilitates use of system 100′ to produce many visual effects, such as strobe lighting effects. Although only one LED is shown for each phase in this example, it will be appreciated that several LEDs can be connected in parallel, if low voltage V+ is used, or in series if high voltage is used, or in any suitable combination of serial and parallel connections, depending on the voltage and current requirement.
Similarly, a gating bipolar junction transistor TG2 is provided to control the entire ladder 704. This allows selective enabling of analog-to-analog converters connected to the uni-directional coupling unit 106. For example, an alternative analog-to-analog converter (not shown) can be connected to the uni-directional coupling unit 106, operation of which is enabled through another gating transistor (not shown). Which analog-to-analog converter is enabled therefore depends on which gating transistor is ramped on. The gating transistor TG2 therefore provides a selection function, allowing selection of one of analog-to-analog converters to transmit multi-channel output signals to the data bus.
The output values from this conversion engine can be delivered to the analog data bus 108 and to drive the multi-channel drive module, namely a gate/interface component 110, in the same manner as described above. In this example, the input is relative position of the light source 802 in reference to each of the light detectors arranged on the base 808. As will be appreciated, any relative motion between the light source and the base can be used to vary the input signal and therefore generate the multi-channel output signals. The relative position can be varied manually, using a dial, or driven by the variation of another input signal, such as temperature or voltage of a power supply. The variation of relative position also can be achieved by moving the base 808 relative to a fixed light source 802. Light detectors 806 also may be arranged on a wheel and the rotation of the wheel relative to the fixed light source may be utilized for converting an analog signal to a multi-channel analog output signals. An input signal can be utilized to drive a stepper motor (not shown) to rotate the wheel, thereby driving the generation of multi-channel analog output signals.
It will be appreciated that conversion from a single-channel analog signal can be achieved in many different ways, not restricted to examples provided herein. Some further examples are provided below, for illustration. For example, magnetic coupling based on magnetic induction may be utilized. A magnet may be used as a primary coupling element and a number of coils may be used as secondary coupling elements. In response to motion of the magnet in the vicinity of the coils, current may be generated in these coils as output signals. Similarly, a primary coil can be used as a primary coupling element. A plurality of secondary coils can be arranged in a manner similar to that of light detectors illustrated in
As also will be appreciated, the unidirectional coupling unit is not required to use diodes. Other uni-directional couplers can be used. For example, in one alternative embodiment, photo-electric coupling is used. This is illustrated in
Various embodiments of the invention have now been described in detail. Those skilled in the art will appreciate that numerous modifications, adaptations and variations may be made to the embodiments without departing from the scope of the invention. Since changes in and or additions to the above-described best mode may be made without departing from the nature, spirit or scope of the invention, the invention is not to be limited to those details but only by the appended claims.